No Difference in Cardiovascular Events with Cooler Dialysate

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The use of personalized cooler dialysate—36°C or lower—does not reduce the risk of cardiovascular events among maintenance hemodialysis patients, concludes a randomized trial in The Lancet.

The pragmatic, open-label Major Outcomes with Personalized Dialysate TEMPerature (MyTEMP) trial was carried out at 84 hemodialysis centers in Ontario, Canada. With covariate-constrained randomization, centers were assigned to use a personalized cooler dialysate—0.5°C–0.9°C lower than the patient's body temperature; lowest recommended temperature, 35.5°C—or a standard dialysate temperature of 36.5°C.

The two groups were compared on a primary composite outcome of cardiovascular-related death or hospitalization for myocardial infarction, ischemic stroke, or congestive heart failure. Primary outcomes were recorded in Ontario databases by medical coders who were unaware of the study.

Over the 4-year study, the centers provided approximately 4.3 million hemodialysis treatments to 15,413 patients. Median follow-up was 1.8 years. Mean dialysate temperature was 35.8°C in the intervention group and 36.4°C in the standard treatment group.

Rates of the primary composite outcome were similar between groups: 21.4% with cooler dialysate and 22.4% with standard-temperature dialysate. Sensitivity and subgroup analyses yielded similar findings. Mean drops in intradialytic systolic blood pressure were 26.6 mm Hg and 27.1 mm Hg, respectively. Other secondary outcomes were comparable as well. Patients assigned to cooler dialysate were more likely to say they felt uncomfortably cold: relative risk, 1.6.

A growing number of dialysis centers have been using cooler dialysate, reflecting the belief that it may lead to improved cardiovascular outcomes. Although some studies have reported lower rates of cardiovascular mortality with cooler dialysate, the overall quality of evidence on this topic is considered low.

The MyTEMP trial shows no difference in cardiovascular mortality or major adverse cardiovascular events at maintenance hemodialysis centers using personalized cooler dialysate compared with standard-temperature dialysate. The study also finds no meaningful difference in mean drop in intradialytic systolic blood pressure or in intradialytic hypotension. The researchers conclude: “A lack of benefit compounded by the likelihood of patient discomfort provides no justification for use of cooler dialysate for all patients as a centre-wide policy” [MyTEMP Writing Committee; Garg AX, et al. Personalised cooler dialysate for patients receiving maintenance haemodialysis (MyTEMP): A pragmatic, cluster-randomised trial. Lancet 2022; 400:1693–1703. doi: 10.1016/S0140-6736(22)01805-0].